In semiconductor processing systems, robots are employed to move wafers from one location to another. For example, one or more robots may be employed to pick up a wafer from a wafer cassette in a loading port, move the wafer to a load lock, move the wafer to one or more intermediate locations (e.g., transfer modules), and move the wafer to a process module or reactor for wafer processing.
To accurately place and pick up wafers, a robot needs to know the coordinates of various locations in the wafer processing system. Coordinates may be programmed into a respective robot during a set-up process after it is installed in the wafer processing system. In that manner, hand-off (e.g., pick and place) locations used by the robot are known. For example, a robot may be used to transfer wafers from a transfer module into a process module, such as to a pedestal center. Typically, the set-up process is performed by a technician or a field service engineer while the process module is cold. However, once the process module is under vacuum or raised to a higher temperature, coordinates of a specific location (e.g., center of a pedestal) within the process module may have moved. Accurate placement of a wafer to a specific location during process conditions is desired to decrease errors incurred during the processing of the wafer, and to achieve smaller form factors for semiconductor devices and/or integrated circuits.
The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
It is in this context that disclosures arise.